This LaTeX file:
\documentclass[twoside]{article}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\makeatletter
\renewcommand{\rmdefault}{ptm}
\renewcommand{\ttdefault}{pcr}
\renewcommand{\sfdefault}{phv}
\usepackage{mtpro2}
\makeatother
\begin{document}
$x$ $\mathsf{x}$ \textsf{x} x
\end{document}
produces the pdf output with sans serif font Helvetica too large.

This LaTeX file:
\documentclass[twoside]{article}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\makeatletter
\renewcommand{\rmdefault}{ptm}
\renewcommand{\ttdefault}{pcr}
\usepackage[scaled=.90]{helvet}
\usepackage{mtpro2}
\makeatother
\begin{document}
$x$ $\mathsf{x}$ \textsf{x} x
\end{document}
produces exactly the same pdf output, with Helvetica still too large.
HELVETICA DOES NOT SCALE.
Why? What can be done?
System:
Up to date texlive 2018 on iMac.
Compiled using pdflatex, and pdf viewed with Apple Preview.
Using adobe type 1 fonts. Same result using urw type 1 fonts.
ADDENDUM -- PROBLEM SOLVED
PROBLEM: \usepackage[scaled=.91]{helvet} was not working
SOLUTION: I had two copies of t1phv.fd on my system. The one in texmf-local did not provide for scaling. I commented it out and now pdflatex uses the other one, located in texmf-dist, which does allow scaling.
NOTE: Package newtxtext breaks \renewcommand{\rmdefault}{bch} . When using it I could not later change rmdefault to Bitstream Charter. Bug in newtxtext IMHO. If only someone would simply break txfonts into txfontstext and txfontsmath without all of the fanciness of newtxfonts, it would be a great service. THANK YOU FOR ALL ANSWERS!
latin9
is an unusual file encoding for mac. Please check if your file really is encoded in latin9.\makeatletter
and\makeatother
. Also, since you are using Times font, you can use\usepackage{newtxtext}
for text followed by\usepackage{mtpro2}
for math. The former sets up Times as the serif font, and Helvetica (automatically scaled at 0.9) as the sans-serif font.